Filter aid conditioners

ABSTRACT

This application discloses a composition comprising a mixture of an oxazoline with a filter aid and to its use in filtering apparatus. This composition facilitates the removal of suspended solids from polymers and its solutions in nonpolar solvents. The preferred oxazolines are 4,4-dihydroxymethyl or 4monohydroxymethyl-2-alkyloxazoline, wherein the alkyl group can range from C6 to C22 in length, but is preferably in the range of C12 to C16.

United States Patent [72] Inventor Bernard J. Davis References CitedBiloxi, Miss. UNITED STATES PATENTS 1 pp No. 789,592 3,252,399 5/1966Rice eta] 210 75x Flled J 3,274,103 9/1966 Adams 210/75x 1 PatentedMel-16,1971 3,242,073 3/1966 Guebert etal. 210/75x Asslgnee Relchholdchemlcalslm 3,368,678 2/1968 Gilbert etal 210/75 Primary Examiner-JohnAdee Attorneys-Munson H. Lane and Munson H. Lane, Jr.

[54] FILTER AID CONDmONERS ASSTRACT: This application diseloses acornposition com- 9 Claims No Drawings prising a mixture of an orrazolmew th a filter aid and to its use m filtering apparatus. This compositionfacilitates the removal [52] U.S. Cl. 210/75, of suspended solids frompolymers and its solutions in non- 210/501 polar solvents. The preferredoxazolines are 4,4-dihydrox- [51] lnLCl 801d 37/02 ymethyl or4-m0nohydroxymethyl-2-alky1oxazoline, wherein [50] Field of Search210/75, the alkyl group can range from C to C in length, but ispreferably in the range of C to C FILTER AID CONDITIONERS The inventionrelates to a composition and method for improving the properties offilter aids in nonaqueous systems so that these modified filter aids caneasily form strong, free flowing filtration beds to remove suspendedsolids from polymers or essentially nonaqueous polymer solutions inrelatively nonpolar solvents, lubricants, vegetable oils and similarsystems wherein difficulty is met in properly wetting, and depositing afree and rapid filtration bed composed of a good precoat on the filtersof the filtration system for removal of solids from polymer solutions oroils.

More specifically the invention relates to a composition comprising amixture of an oxazoline with a filter aid and to its use in filteringapparatus. This composition facilitates the removal of suspended oilsfrom polymers and its solutions in nonpolar solvents. The preferredoxazolines are 4,4-dihydroxymethyl or 4-monohydroxymethyll-2-alkyloxazoline, wherein the alkyl group can range from C,- to C inlength,v but is preferably in the range of C to C In the removal ofsolids from polymer solutions, various filtration means are used in wellestablished unit operations for the separation of solutes from theirsolids. In some applications, the filter zone is prepared by the buildupof a precoat material on the filter cloth. Uniform thickness and holdingpower by the filter cloth of the precoat is quite important for goodfiltration. The preliminary, but fundamentally necessary step ofpreparing a satisfactory precoat is also subject to many complications.

One particularly troublesome difficulty exists because of theunavoidable moisture content in the filter aid hydrocarbon slurry. Thereis a tendency for the filter aid slurry, either while being employed toprecoat, or during the filtration operation, itself, to agglomerate onthe filter cloth in the primary filter zone. This agglomeration resultsin an uneven precoat which markedly increases the susceptibility of theprecoat to breakthroughby the suspended solids of the solute, due toinadequate coating on areas of the filter cloth.

There is also a marked tendency for the precoat to fall off the filtercloth by slumping when any significant variations in the filterthroughput rate are experienced. This precoat failure destroys thefiltration function completely and the filters must undergo theexpensive, time consuming procedure of building up a new precoat, duringwhich time the filtration unit cannot perform its removal function.

In the previous art it was found that some satisfactory results could beobtained by carefully controlling the water content of the filteraid-hydrocarbon slurry which goes to form the precoat. The filter aid,usually a commercially available mineral, such as diatomaceous earth,synthetic silicas, asbestosfibers, and asbestos fibers, and cellulosefibers, are available as supplied with a water content ranging between200*300 parts per million. It is impractical to further calcine thesematerials or fibers, as supplied, to reduce the water content to whathas been accepted as acceptable levels.

Furthermore, the diatomaceous earth comprises only a few weight percentof the hydrocarbon solvent when converted to slurry for deposition onthe filters. The prior art carefully controlled the water content tonarrow limits by predrying streams so that the final water content inthe system being filtered was no more than 3050 parts per million.

Therefore it becomes an object of this invention to provide animprovement of filter aids in nonaqueous systems.

Another object is to provide modifiers for filter aids with markedsurface activity in nonaqueous systems.

A further object is to provide modifiers for filter aid which activelytrap water in nonaqueous filtration systems.

given by way of illustration only, since various changes andmodifications within the spirit and scope of the invention will becomeapparent to those skilled in the art from this detailed description.

In accordance with this invention it has been found that certainmaterials having marked surface activity occlude the hydrogen bondingsites on the filter aid, actively trap water present in the system inthis occluded layer, leaving a lyophilic layer exposed on the surface ofeach filter aid particle so that no adverse forces are exerted to reducethe rate of filtration over the cohesive strength of the precoat toitself or to the flter cloth. The resultant system is essentiallyinsensitive to water being present at levels as high as 500 parts permillion and actually serves to remove this water as an entrapped waterin oil layer during filtration. Furthermore, it has been foundthat thesemodifiers also exert a suspending effect on the filter aid to preventpacking and agglomeration yet allow the filter aid to form a fixedcohesive, free flowing bed. It has been discovered that the mosteffective filter aid treating agents are members of a family ofsubstituted oxazolines having the fol wherein R is a straight chainparaffin or olefin with a C to C chain length. The C C chains were mosteffective. Ox azolines with no hydroxylmethyl groups were uneffective.The dihydroxylmethyl oxazoline configuration gave better results in thepresence of higher water levels than the monohydroxymethyl derivatives,which in turn were found to be more effective than oxazolines containingno hydroxymethyl groups.

Examples where the above described filter aidconditioner is applicableinclude olefinic polymers, such as polymers from isoprene, piperyleneand the like, or mixed olefins with appended aromatic groups such asstyrene, methylstyrene and the like. They also include terpene resins asderived, e.g. from dipentene, phellandrene, camphene and the like. Theyinclude further aliphatic and aromatic hydrocarbon polymers such asmineral oils, coumaron-indene resin, polymeric oils such as vegetableoils, lubricants and the like.

Evaluation tests were run in plant conditions where above specifiedcompounds were filtered in the absence of a solvent and also dissolvedin a nonpolar solvent. The technique involved is typified by thefollowing example:

EXAMPLE A Piperylene was polymerized at 40 percent solids in xylol using2 percent anhydrous aluminum chloride as a catalyst. Polymerization wasrun at 20 C. When polymerization was completed 5 percent hydrated limewas added for neutralization of the catalyst, and the system heated toC. At this point the system was filtered through a Sparker filter presswherein the precoat was prepared with xylol and diatomaceous earthcontaining a small percentage of asbestos fiber. The efficiency offiltration was measured by the number of gallons of filtrate processedbefore the bed had to be changed. The filter aid modifiers were added tothe prepared filter aid slurry before making the precoat bed on thefilter by simply stirring it into the solvent-filter aid system. Theamount of modifier can vary between about 0.025 and about 1.0 percent byweight on the weight of the filter aid with little effect on itsefficiency.

Over 1.0 percent was deemed wasteful.

Initial laboratory tests demonstrated that the dihydroxymethyl oxazolinederivative was most effective in systems containing up to 500 parts permillion water and that of this type of oxazoline those having hydrophobechains of C to C were most effective. The oxazoline derivative employedin examples IVI had the following structure.

Such compounds are manufactured by Reichhold Chemicals, lnc., WhitePlains, N.Y., under the name Deltazoline, with the above particular typecalled Deltazoline A 14.

EXAMPLES I-VI Runs were made employing the piperylene resin solutiondescribed above.

TABLE 1 Percent Deltazoline A- 1 4 5 5 8ft 2 of filter area 1 nonePrecoat not acceptable for filtration due to agglomeration 1.0 35,000gallons/cycle 0.5 34,000 gallons/cycle 0.1 35,000 gallons/cycle 0.0533,000 gallons/cycle 0.025 32,000 gallons/cycle 0.01 10,000gallons/cycle It can be seen above that the marked efficiency of theoxazoline derivative is evidenced in concentration of 0.025 percent byweight of the filter aid or over.

I claim:

1. A method of removing solids from a polymer which comprises filteringthe same with the aid of a composition comprising a mixture of at leastone oxazoline selected from the group having the formulas wherein R isselected from a group consisting of paraffins and olefins having 8through 22 carbon atoms, with a filter aid.

2. A method as defined in claim 1 wherein the polymer is dissolved in anonpolar solvent.

3. A method as defined in claim 1 wherein the polymer is an 5 alipathichydrocarbon.

Filtration Capacity of by wei ht based on the filter aid used.

8. T e method according to claim 1, wherein the oxazoline is selectedfrom a group consisting of 4,4-dihydroxymethyl and4-monohydroxymethyl-2-alkyloxazoline, wherein the alkyl group can rangefrom C to C in length.

9. The method according to claim 8 wherein the alkyl group has a rangeof C to C in length.

2. A method as defined in claim 1 wherein the polymer is dissolved in anonpolar solvent.
 3. A method as defined in claim 1 wherein the polymeris an alipathic hydrocarbon.
 4. A method as defined in claim 1 whereinthe polymer is an aromatic hydrocarbon.
 5. A method as defined in claim1 wherein the polymer is a mineral oil.
 6. A method as defined in claim1 wherein the polymer is a vegetable oil.
 7. The method according toclaim 1, wherein the amount of oxazoline ranges from about 0.25 percentto about 1 percent by weight based on the filter aid used.
 8. The methodaccording to claim 1, wherein the oxazoline is selected from a groupconsisting of 4,4-dihydroxymethyl and4-monohydroxymethyl-2-alkyloxazoline, wherein the alkyl group can rangefrom C6 to C22 in length.
 9. The method according to claim 8 wherein thealkyl group has a range of C12 to C16 in length.